- Jackson County)
(From Atlas of Oregon Lakes, Johnson et al. 1985). Applegate Lake is a Corps of Engineers reservoir in southwestern Oregon just north of the California border. The project was developed in 1980 (construction began in 1976) by damming the mainstream of the Applegate River 46 miles upstream from its confluence with the Rogue. The river and hence the lake derives its name from Lindsay Applegate, a prominent early Oregon pioneer of this region. Applegate Lake is the second large, multipurpose water resource project in the basin, Lost Creek Lake being the other. Both are components of the Rogue River Basin Project.
The contributing drainage basin is almost totally within the Rogue River National Forest of Oregon and California, although there are some scattered parcels of private land. The tributaries rise in the Siskiyou Mountains, a rugged area of mostly ancient metamorphic rocks covered with a thick forest. Shoreline topography is relatively steep in most places, although several smaller areas of flatter slopes exist, offering the potential for development and access. Development of recreational sites around the lake by the Corps of Engineers has been minimal. The wilderness setting has been retained as much as possible and a hiking trail follows the shoreline around the lake. A 10 mph speed limit for boats is enforced at the lake. Applegate Lake reaches a maximum depth of 225 feet just behind the dam and has a mean depth of 83 feet. The rise of water behind the dam has flooded parts of several tributaries of the Applegate River giving the reservoir a highly branched, dendritic shape. Consequently, the length of shoreline is extensive. The design of the dam facility allows water to be withdrawn from any of several depths. Therefore, because of temperature stratification in the reservoir, it is possible to cool the river downstream in the summer by selectively discharging deeper water.
Water in Applegate Lake has chemical characteristics which are about average for the region and the lake is classified as mesotrophic. The concentrations of magnesium and calcium are above average, due to the weathering of sedimentary rock in the basin. The concentrations of phosphorus and chlorophyl are also above average and water transparency is fairly high (15.1 feet; 4.6 meters). There is no evidence of oxygen depletion or algal blooms in the lake, although the pH is somewhat high.